Also called linespacing. The amount of vertical space between lines of type. The term leading comes from the thin strips of lead placed between lines of text to add vertical space to fill pages in metal type printing presses. To this day, increasing leading is referred to as adding lead. Most software programs auto-set leading by default to a 1:1.2 (120%) ratio, which fits nicely at 10pt type with 12pt leading, but starts to use fractional points on different sizes (11/13.2).